Method and apparatus for horizontal assembly of a high-voltage feed-through bushing

ABSTRACT

A method for horizontal assembly of a high-voltage feed-through bushing includes vertically-assembling a field shaper assembly of a high-voltage feed-through bushing on a field shaper fixture. The field shaper assembly is then rotated within the field shaper fixture such that the field shaper assembly is oriented on a horizontal axis. Next, an insulator tube fixture supporting an insulator tube assembly is positioned adjacent to the field shaper fixture. The insulator tube assembly, being oriented on the same horizontal axis as the field shaper assembly, is then affixed to field shaper assembly.

FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT

The Method and Apparatus for Horizontal Assembly of a High-VoltageFeed-Through Bushing is assigned to the United States Government and isavailable for licensing for commercial purposes. Licensing and technicalinquiries should be directed to the Office of Patent Counsel, Space andNaval Warfare Systems Center, San Diego, Code 20012, San Diego, Calif.,92152; telephone (619)553-3001, facsimile (619)553-3821.

TECHNICAL FIELD

The Method and Apparatus for Horizontal Assembly of a High-VoltageFeed-Through Bushing generally relates to assembly fixtures and inparticular but not exclusively, relates to assembly fixtures forhigh-voltage bushings.

BACKGROUND

Most high voltage bushings have one dielectric tube external to abuilding or container. Feed-through bushings that exit from a buildingoften have a second dielectric tube internal to the building. The tubesare usually joined together by a coupling where the bushing passesthrough the building. Often the tubes are sealed and pressurized withair, nitrogen (N2) or sulfur hexaflouride (SF6) to increase thewithstand voltage between a high voltage center conductor mounted in thebushing and the ground potential at the point where they penetrate thebuilding. The dielectric tubes are most commonly made out of fiberglasscovered with silicone rubber materials. Recently, these bushings haveincluded internal field shapers for moderating the electric field alongthe bushing. U.S. Pat. No. 6,951,987, entitled, “High Voltage Bushing”describes an exemplary embodiment of a bushing utilizing an internalfield shaper.

High-voltage feed-through bushings typically weigh thousands of poundsand may be up to twenty feet in length. Typically, these bushings areassembled vertically. Vertical assembly of these high-voltagefeed-through bushings presents a number of problems. First, assemblingthe bushing outdoors could result in physical dangers to personnel anddamage to equipment as a result of inclement wind and weather. Second,assembly outdoors presents a greater risk of contamination within theinterior of the bushing. Third, assembling the bushing indoors requiresvery tall facilities. Fourth, expensive and heavy-duty over-head hoistsor cranes are required for vertical assembly of bushings. Fifth,alignment with vertical assembly can be difficult and hazardous becauseof the need for an individual to be present at the height of assembly.

The process of assembling a high-voltage feed-through bushing should berelatively safe and inexpensive, should minimize the chance ofcontamination of the interior of the bushing, and should not requirespecialized facilities.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the invention aredescribed with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified.

FIG. 1 is a cross-sectional view of a high-voltage feed-through bushing.

FIG. 2A is a top view of a field shaper fixture, in accordance with anembodiment of the invention.

FIG. 2B is a front view of a field shaper fixture, in accordance with anembodiment of the invention, coupled to a field shaper assembly in ahorizontal position.

FIG. 2C is a front view of a field shaper fixture, in accordance with anembodiment of the invention, coupled to a field shaper assembly in avertical position.

FIG. 2D is a top view of a mounting paddle, in accordance with anembodiment of the invention.

FIG. 3A is a side view of an insulator tube fixture, in accordance withan embodiment of the invention.

FIG. 3B is a front view of an insulator tube fixture, in accordance withan embodiment of the invention.

FIG. 3C is a front view of an insulator tube fixture, in accordance withan embodiment of the invention, supporting an insulator tube assembly.

FIG. 4A is a front view of a center conductor fixture, in accordancewith an embodiment of the invention.

FIG. 4B is a side view of a center conductor fixture, in accordance withan embodiment of the invention.

FIG. 4C is a side view of a center conductor fixture, in accordance withan embodiment of the invention, coupled to a center conductor assembly.

FIG. 5 is a top view of a field shaper fixture positioned adjacent to aninsulator tube fixture, in accordance with an embodiment of theinvention.

FIG. 6 is a top view of a center conductor fixture positioned adjacentto an insulator tube fixture, in accordance with an embodiment of theinvention.

FIG. 7 is a flow-chart illustrating a process of assembling ahigh-voltage feed-through bushing, in accordance with an embodiment ofthe invention.

DETAILED DESCRIPTION

Embodiments of a Method and Apparatus for Horizontal Assembly of aHigh-Voltage Feed-Through Bushing are described herein. In the followingdescription numerous specific details are set forth to provide athorough understanding of the embodiments. One skilled in the relevantart will recognize, however, that the techniques described herein can bepracticed without one or more of the specific details, or with othermethods, components, materials, etc. In other instances, well-knownstructures, materials, or operations are not shown or described indetail to avoid obscuring certain aspects.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Thus, theappearances of the phrases “in one embodiment” or “in an embodiment” invarious places throughout this specification are not necessarily allreferring to the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments.

FIG. 1 is a cross-sectional view of a high-voltage feed-through bushing100. The illustrated application of bushing 100 includes field shaper102, center plate 104, intermediate plate 106, insulator tubes 108 and110, center conductor 112, end plates 114 and 116, and socket 118. Theterm “field shaper assembly” as used herein is intended to refer to anassembled structure that includes, at least, field shaper 102, centerplate 104, and intermediate plate 106. The term “center conductorassembly” as used herein is intended to refer to an assembled structurethat includes, at least, center conductor 112 and end plate 114. Theterm “insulator tube assembly” as used herein is intended to refer to anassembled structure that includes, at least, insulator tube 108 orinsulator tube 110.

FIGS. 2A, 2B, and 2C illustrate various views of a field shaper fixture200, in accordance with an embodiment of the invention. The illustratedembodiment of field shaper fixture 200 includes base 202, verticalsupport members 204, mounting paddles 206, wheels 208, and rotatingjoints 210. FIG. 2A illustrates a top view of field shaper fixture 200,in accordance with an embodiment of the invention. FIG. 2B illustrates afront view of field shaper fixture 200 with field shaper assembly 214 ina horizontal position (aligned along horizontal axis 217), in accordancewith an embodiment of the invention. FIG. 2C illustrates a front view offield shaper fixture 200 with field shaper assembly 214 in a verticalposition, in accordance with an embodiment of the invention.

The support stand of the illustrated embodiment of field shaper fixture200 includes base 202, two vertical upright members 204 and wheels 208.In one embodiment, four wheels 208 may be attached to base 202, one oneach corner of base 202. Various numbers and configurations of wheelsmay be implemented in conjunction with base 202, such that field shaperfixture 200 is capable of being positioned in various locations forassembly of bushing 100.

By way of example, base 202 may be built with 2ea 4″×2.66″×0.190″×48″Laluminum I-beams set 55″ apart with a 2½″×2½″×¼″ aluminum cross memberangle bolted to the I-beam at the centerline. 4ea 4″ casters may also beattached to the bottom of the I-beams at the outside corners. Inaddition, 2ea ½″×2″ aluminum flat bar braces may be attached at anglefrom the cross member angle to the top of the I-beams on both sides.

In one embodiment, vertical support members 204 may be built with 2ea3″×1.41″×0.170″×30″L aluminum channel pieces attached to the crossmember angle and perpendicular to the I-beam on either side. 2ea ½″×2″aluminum flat bar braces may also be attached to the edge of the channelat angle to a bracket on the top of the I-beam on both sides.

The illustrated embodiment of field shaper 200 further includes twomounting paddles 206. Mounting paddles 206 are adapted for coupling to afield shaper assembly of bushing 100 and are capable of rotating abouthorizontal axis 212. Mounting paddle 206 is coupled to vertical uprightmember 204 by way of mounting joint 210. In one embodiment, mountingjoint 210 may include a pillow block bearing assembly. Pillow blockbearing assembly may be secured to slotted holes in vertical uprightmember 204 to allow for height adjustments of mounting paddle 206.

FIG. 2D illustrates one embodiment of mounting paddle 206 in moredetail. Mounting paddle 206 includes a shaft 218 and a mounting plate220. One end of shaft 218 is coupled to mounting joint 210. In oneembodiment, shaft 218 may be coupled to mounting joint 210 such thatmounting paddle 206 is capable of being adjusted linearly alonghorizontal axis 212. Shaft 218 may also include a locking plate to allowmounting paddle 206 to be locked into either a vertical or a horizontalposition.

A second end of shaft 218 is coupled to mounting plate 220. Mountingplate 220 is adapted to allow the mounting plate to be temporarilysecured to field shaper assembly 214. The illustrated embodiment ofmounting plate 220 includes a concave edge opposite shaft 218, but it isrecognized that various edge shapes may be implemented to provideclearance for field shaper assembly 214.

Also included in mounting plate 220 are mounting apertures 222(a)-(c).In one embodiment, mounting apertures 222(a)-(c) may be through-holesfor allowing plate 220 to be temporarily bolted to field shaper mountingholes 216, as shown in FIG. 2B. In addition, mounting apertures222(a)-(c) are disposed on an arc 228 that is defined by thecircumference of field shaper mounting holes 216. In one embodiment,mounting plate 220 may include additional mounting apertures 224.Mounting apertures 224 may be used in conjunction with mounting aperture222 a for securing mounting plate 220 to a different field shaperassembly with a second diameter.

Mounting plate 220 may also include clearance apertures 226. Assemblingfield shaper assembly 214 may require bolting center plate 104 tointermediate plate 106. Clearance apertures 226 are for allowing accessto these assembly bolts of field shaper assembly 214.

FIGS. 3A, 3B, and 3C illustrate various views of an insulator tubefixture 300, in accordance with an embodiment of the invention. Theillustrated embodiment of insulator tube fixture 300 includes base 302and resting cradle 304. FIG. 3A illustrates a side view of insulatortube fixture 300, in accordance with an embodiment of the invention.FIG. 3B illustrates a front view of insulator tube fixture 300. FIG. 3Cillustrates a front view of resting cradle 304 supporting an insulatortube assembly 308 in a horizontal position (aligned along horizontalaxis 217).

By way of example, insulator tube fixture 300 may be constructed of 2ea4″×2.66″×0.190″×37.5″L and 2ea 4″×2.66″×0.190″×49.5″ aluminum I-beamsfor adjustable side rails 48″ apart. 2ea adjustment support structuresconsisting of 2ea 3″×1.41″×0.170″×36″ aluminum channel pieces and 8ea½″×2″×7″L aluminum flat bar are attached to I-beam side rails to allowfor length adjustment of insulator tube fixture 300 to fit insulatortube assemblies of various lengths. A support channel may be attached tothe top and bottom of each side rail with aluminum flat bar partsattached vertically to outside edges of the channel at both ends andspaced through middle of length. I-beams and channel pieces are bothmachined with attaching holes for length adjustment. 2ea4″×2.66″×0.190″×42⅝″L aluminum I-beams may be attached with brackets toboth ends of the side rail I-beams. 2ea 2½″×2½″×¼″×8″L aluminum anglepieces are attached at either end to help support radius end plates 114and 116. 2ea 3″×1.41″×0.170″×24″L aluminum channel pieces are attachedvertically to an angle cross brace at each end of insulator tube fixture300. 4ea ½″×2″ aluminum flat bar braces are attached at angle from theupright channel to top of I-beam side rails at all 4 corners. 4ea 6″heavy-duty casters may be mounted at outside corners to allow insulatortube assembly 300 to be easily moved for assembling bushings 100.Resting cradles 304 and 306 may be fabricated as plywood inserts, 2eaper cart/fixture. Resting cradle 304 is made to facilitate one bushingsize and resting cradle 306 is made to facilitate a second bushing 100size. By way of example, for a 24″ bushing, resting cradles 304 may bemade from a minimum ¾″ plywood, 47.5″W×22″H and with a 12.5″ radius cutat the center dimensions of 23.75″×23″. For a 30″ bushing resting cradle306 may be made from a minimum ¾″ plywood 47.5″W×21.5″H and with a 17.25radius cut at the center dimensions of 23.75″×23″. The dimensions forthe radius center are calculated to locate the centerline of theinsulator tube assembly 308 with horizontal axis 217.

FIGS. 4A, 4B, and 4C illustrate various views of a center conductorfixture 400, in accordance with an embodiment of the invention. Theillustrated embodiment of center conductor fixture 400 includes base402, vertical upright member 404, vertical upright backplate 406,mounting holes 407, wheels 408, and support shelf 410. FIG. 4Aillustrates a front view of center conductor fixture 400, in accordancewith an embodiment of the invention. FIG. 4B illustrates a side view ofcenter conductor fixture 400, in accordance with an embodiment of theinvention. FIG. 4C illustrates a side view of center conductor fixture400 with a center conductor assembly 414 in a horizontal position(aligned along horizontal axis 217).

The support stand of the illustrated embodiment of center conductorfixture 400 includes base 402, vertical upright member 404, verticalupright backplate 406, and wheels 408.

By way of example, base 402 may be constructed of 2ea4″×2.66″×0.190″×72″L aluminum I-beams set 55″ apart with a4″×2.66″×0.190″×49.625″L I-beam bolted with brackets to one end. A2½″×2½″×¼″ aluminum angle bolted 24″ from same end, both cross braces tomaintain 55″ width to allow clearance for insulator tube fixture 300.

In one embodiment, vertical support member 404 may be built with 2ea3″×1.41″×0.170″×30″L aluminum channel pieces attached to the angle crossmember perpendicular to the I-beam on either side. 2ea ½″×2″ aluminumflat bar braces are attached to the channel at angle to the top of theI-beam cross member at rear of fixture. 2ea 3″×1.41″×0.190″×34″Laluminum channel pieces are attached vertically to the angle crossmember 34″ apart with 2½″×2½″×¼″ aluminum angle braces boltedhorizontally to side of channel and rear cross brace I-beam. 2ea2½″×2½″×¼″ aluminum angle braces are attached to the channel at angle tothe top of the I-beam cross member. A 2½″×2½″×¼″ aluminum angle piecemay be machined for attachment to 4ea aluminum channel uprights at thetop of the 30″ channel.

Support shelf 410 may be constructed from a 2½″×2½″×¼″×55″L aluminumangle piece and mounted horizontally across the channel uprights forsupporting endplate 114 of center conductor assembly 414. The channeluprights may be drilled for adjustable height attachment of supportshelf 410 such that the centerline of center conductor assembly 414 isaligned with horizontal axis 217.

Vertical upright backplate 406 may be fabricated from a ⅜″×18″×48″aluminum plate machined with mounting holes 407 and attached to thechannel uprights on vertical upright member 404. 4″ casters may beattached to the bottom outside corners of base 402 to allow centerconductor fixture 400 and a center conductor assembly 414 to be easilypositioned for assembly into an insulator tube assembly 408.

In the illustrated embodiment of FIG. 4C, center conductor fixture 400includes a center conductor support 412. Center conductor support 412 isfor providing temporary support to center conductor 112 during assemblyof bushing 100. Center conductor support 412 may include 2ea wood 2×4's5 feet long and 1ea 2×4×22.5″ long attached perpendicular to and at thecenter of the five foot boards with one on each side.

In addition, a weight may be placed on the back of the fixture to helpcounterbalance the weight of center conductor assembly 414. By way ofexample, a twenty-five pound lead weight may be utilized.

FIG. 5 is a top view of field shaper fixture 200 positioned adjacent toinsulator tube fixture 300, in accordance with an embodiment of theinvention. FIG. 6 is a top view of center conductor fixture 400positioned adjacent to insulator tube fixture 300, in accordance with anembodiment of the invention. As mentioned previously, the correspondingwidths of field shaper fixture 200, insulator tube fixture 300, andcenter conductor fixture 400 are such that the fixtures may bepositioned adjacent to one another for horizontal assembly of bushing100.

FIG. 7 is a flow chart illustrating a process 700 for horizontalassembly of a high-voltage feed-through bushing, in accordance with anembodiment of the invention. Process 700 is described with reference toFIGS. 1-7.

In process block 702, field shaper assembly 214 is assembled in avertical position. First, field shaper fixture 200 is locked into avertical build position. The vertical build position includes themounting plates 220 of mounting paddles 206 oriented substantiallyhorizontal. Next, intermediate plate 106 is temporarily bolted tomounting paddles 206 via mounting apertures 222(a)-(c). Field shaper 102is then placed into intermediate plate 106. Center plate 104, with ano-ring, is then place over field shaper 102 and bolted to intermediateplate 106 utilizing clearance apertures 226 where necessary.

In process block 704, field shaper fixture 200 is unlocked from itsvertical build position and field shaper assembly 214 is rotated aboutaxis 212 such that field shaper fixture is locked into a horizontalbuild position. The horizontal build position includes field shaperassembly 214 being aligned along horizontal axis 217. Alignment pins arethen inserted into center plate 104.

In process block 706, insulator tube fixture 300, supporting insulatortube assembly 308 with o-rings on both ends, is positioned adjacent tofield shaper fixture 200, as shown in FIG. 5, using the alignment pinsas a guide.

In process block 708, the insulator tube assembly 308 and field shaperassembly 214, both being aligned on horizontal axis 217, are affixed toone another via multiple bolts. The alignment pins are then removed fromcenter plate 104.

In process block 710, the temporary bolts securing field shaper assembly214 to mounting paddles 206 are removed. Next, field shaper fixture 200is removed, leaving field shaper assembly 214 and insulator tubeassembly 308 supported by insulator tube assembly 308. Alignment pinsare then inserted into intermediate plate 106.

In process block 712, a second insulator tube assembly 308, with o-ringson both ends, supported by a second insulator tube assembly 300 ispositioned adjacent to field shaper assembly 214, such that the secondinsulator tube assembly 308 is oriented along horizontal axis 217, usingthe alignment pins in intermediate plate 106 as a guide.

In process block 714, the second insulator tube assembly 300 is affixedto field shaper assembly 214 via multiple bolts and the alignment pinsare removed from intermediate plate 106.

In process block 716, end plate 114 is temporarily bolted to verticalupright backplate 406 of center conductor fixture 400, via mountingholes 407. Next, center conductor 112 is bolted horizontally to endplate 114, while temporarily being supported by center conductor support412. Next, a 4″ diameter PVC pipe is inserted through both insulatortube assemblies 308 and field shaper assembly 214. Alignment pins arethen inserted into end plate 114 and center conductor fixture 400 ispositioned adjacent to one of the insulator tube assemblies 308, untilcenter conductor 112 is inserted into the PVC pipe for support. Next,center conductor support 412 is removed and center conductor fixture 400is positioned, as shown in FIG. 6, using the alignment pins in end plate114 as a guide.

In process block 718, insulator tube assembly 300 is affixed to centerconductor assembly 414 via multiple bolts and the alignment pins areremoved from end plate 114. Next, center conductor assembly 414 isdetached from center conductor fixture 400 and center conductor fixture400 is removed.

Lastly, the PVC pipe support is removed from center conductor 112.Endplate 116 with socket 118 is then bolted to the second insulator tubeassembly 308, utilizing temporary alignment pins inserted into endplate116.

1. An apparatus comprising: a support stand having a base and a firstvertical upright member; and a first mounting paddle adapted forcoupling to a field shaper assembly of a high-voltage feed-throughbushing, said first mounting paddle mounted to an upper portion of saidfirst vertical upright member such that said first mounting paddle isrotatable about a horizontal axis.
 2. The apparatus of claim 1, whereinsaid base includes wheels.
 3. The apparatus of claim 1, wherein saidsupport stand further comprises a second vertical upright member.
 4. Theapparatus of claim 3, wherein said apparatus further comprises a secondmounting paddle adapted for coupling to said field shaper assembly, saidsecond mounting paddle mounted to an upper portion of said secondvertical upright member such that said second mounting paddle isrotatable about said horizontal axis, said second mounting paddleopposing said first mounting paddle.
 5. The apparatus of claim 4,wherein said mounting paddles are linearly adjustable along saidhorizontal axis such that field shaper assemblies of various diametersmay be coupled to both said mounting paddles.
 6. The apparatus of claim1, wherein said first mounting paddle comprises: a shaft having a firstand second end portion, said first end portion mounted to said upperportion of said first vertical upright member; and a mounting plateattached to said second end portion of said shaft, wherein said mountingplate includes at least two mounting apertures disposed on an arcdefined by a circumference of mounting holes on said field shaperassembly, said mounting apertures for securing said mounting plate tosaid field shaper assembly.
 7. The apparatus of claim 6, wherein saidmounting plate further comprises at least two clearance apertures forallowing access to assembly bolts of said field shaper assembly.
 8. Asystem comprising: a field shaper fixture having: a support standincluding a base and a first and second vertical upright member; and afirst and second mounting paddle adapted for coupling to a field shaperassembly of a high-voltage feed-through bushing, each mounting paddlemounted to an upper portion of a respective said vertical upright membersuch that said mounting paddles are rotatable about a first horizontalaxis and said second mounting paddle opposes said first mounting paddle;a center conductor fixture having: a support stand including a base anda vertical upright backplate adapted for coupling to a center conductorassembly of said high-voltage feed-through bushing, such that a centerconductor of said center conductor assembly is substantially oriented ona second horizontal axis; and a first insulator tube fixture having: asupport stand including a base and a resting cradle adapted forsupporting a first insulator tube assembly of said high-voltagefeed-through bushing, such that said first insulator tube assembly issubstantially oriented on said second horizontal axis; a secondinsulator tube fixture having: a support stand including a base and aresting cradle adapted for supporting a second insulator tube assemblyof said high-voltage feed-through bushing, such that said secondinsulator tube assembly is substantially oriented on said secondhorizontal axis; wherein said field shaper fixture and said insulatortube fixtures are capable of being positioned such that said fieldshaper assembly may be fixedly attached to both said first and secondinsulator tube assemblies while oriented along said second horizontalaxis; and wherein said center conductor fixture is capable of beingpositioned such that said center conductor assembly may be fixedlyattached to both of said first and second insulator tube assemblieswhile oriented along said second horizontal axis.
 9. The system as inclaim 8, wherein the base of at least one of said support stands furtherincludes wheels.
 10. The system as in claim 8, wherein each saidmounting paddle further comprises: a shaft having a first and second endportion, said first end portion mounted to said upper portion of saidrespective said vertical upright member; and a mounting plate attachedto said second end portion of said shaft, wherein said mounting plateincludes at least two mounting apertures disposed on an arc defined by acircumference of mounting holes on said field shaper assembly, saidmounting apertures for securing said mounting plate to said field shaperassembly.
 11. The system as in claim 8, wherein said mounting paddlesare linearly adjustable along said first horizontal axis such that fieldshaper assemblies of various diameters may be coupled to both saidmounting paddles.
 12. A method comprising: vertically-assembling a fieldshaper assembly of a high-voltage feed-through bushing on a field shaperfixture; rotating said field shaper assembly within said field shaperfixture, such that said field shaper assembly is oriented substantiallyon a horizontal axis; positioning a first insulator tube fixtureadjacent to said field shaper fixture, said first insulator tube fixturesupporting a first insulator tube assembly oriented substantially onsaid horizontal axis; and affixing said field shaper assembly to saidfirst insulator tube assembly.
 13. The method of claim 12, furthercomprising: removing said field shaper fixture from said field shaperassembly, such that said first insulator tube fixture supports both saidinsulator tube assembly and said field shaper assembly; positioning asecond insulator tube fixture adjacent to said first insulator tubefixture, said second insulator tube fixture supporting a secondinsulator tube assembly oriented substantially on said horizontal axis;and affixing said field shaper assembly to said second insulator tubeassembly.
 14. The method of claim 13, wherein said positioning furtherincludes relocating at least one of said fixtures with respect toanother said fixture.
 15. (canceled)
 16. The method of claim 13, furthercomprising: positioning a center conductor fixture adjacent to one ofsaid insulator fixtures, said center conductor fixture supporting acenter conductor assembly oriented substantially on said horizontalaxis; and affixing said center conductor assembly to at least one ofsaid insulator tube assemblies.
 17. The method of claim 16, wherein saidpositioning further includes relocating at least one of said fixtureswith respect to another of said fixtures.
 18. The method of claim 12,wherein said positioning further includes relocating at least one ofsaid fixtures with respect to another said fixture.
 19. The method ofclaim 12, further comprising locking said field shaper fixture into ahorizontal position.
 20. The method of claim 16, further comprisingproviding means for supporting a center conductor of said centerconductor assembly while said center conductor fixture is positionedadjacent to one of said insulator fixtures.